The Structure and Dynamics of Linguistic Networks

Human beings as a species is quite unique to this biological world for they are
the only organisms known to be capable of thinking, communicating and pre-
serving potentially an in¯nite number of ideas that form the pillars of modern
civilization. This unique ability is a consequence of the complex and powerful
human languages characterized by their recursive syntax and compositional
semantics [40]. It has been argued that language is a dynamic complex adap-
tive system that has evolved through the process of self-organization to serve
the purpose of human communication needs [80]. The complexity of human
languages have always attracted the attention of physicists, who have tried to
explain several linguistic phenomena through models of physical systems (see
e.g., [32, 42]).
Like any physical system, a linguistic system (i.e., a language) can be
viewed from three di®erent perspectives [52]. On one extreme, a language is a
collection of utterances that are produced by the speakers of a linguistic com-
munity during the course of their interactions with other speakers of the same
community. This is analogous to the microscopic view of a thermodynamic
system, where every utterance and its corresponding context contributes to
the identity of the language, i.e., the grammar. On the other extreme, a lan-
guage can be characterized by a set of grammar rules and a vocabulary. This
is analogous to a macroscopic view. Sandwiched between these two extremes,
one can also conceive of a mesoscopic view of language, where linguistic enti-
ties, such as the letters, words or phrases are the basic units and the grammar
is an emergent property of the interactions among them.